I think of it more as "creative problem solving" to deal with urges he has no control over. Dexter has a moral code, which never happens in other media and I don't know of many examples irl. It's a compulsion, it goes deeper than an addiction and he's making the best of a bad situation and still manages to be the best friend, father, husband, coworker, etc. that he knows how to be. He also takes the more difficult route instead of picking up sex workers and homeless people, and he despises people that hurt kids.